Injection-molded article for medical use

ABSTRACT

An injection-molded article for medical use obtained by using a medical propylene-ethylene-based resin composition including 88 to 95 parts by mass of a propylene-ethylene resin composition (A) that contains more than 90% and equal to less than 97% by mass of a propylene-ethylene copolymer (a) having an ethylene content of 1 to 5% by mass, and a melt flow rate conforming to JIS K7210 (230° C., 2.16 kg load) being 10 to 100 g/10-min, and equal to more than 3% and less than 10% by mass of a propylene-ethylene copolymer (b) having an ethylene content of 15 to 22% by mass and an MFR of 1 to 50 g/10-min, 5 to 12 parts by mass of an elastomer (B) that is an ethylene-α-olefin random copolymer which is an ethylene-α-olefin random copolymer having a density of 0.880 to 0.920 g/cm 3 ; and 0.01 to 0.20 parts by mass of a weather-resistant stabilizer.

TECHNICAL FIELD

The present invention relates to an injection-molded article for medicaluse using a transparent polypropylene resin composition.

BACKGROUND ART

Propylene-based polymers are excellent in molding processability,mechanical properties, and gas barrier properties, and are thereforemolded by various methods. The molded articles are widely used inapplications, such as food containers, caps, medical instruments,medical containers, daily necessities, automobile parts, electricalparts, sheets, films, and fibers.

Since the propylene-based resin composition used for applications suchas a medical container is subjected to various sterilization treatmentsat the final stage, it is required to have resistance to thesetreatments. Commonly performed sterilization processes includehigh-pressure steam sterilization, ethylene-oxide-gas sterility, andradiation sterility. Radiation sterilization includes sterility by gammaray irradiation and sterility by electron beam, especially ultravioletirradiation.

Patent Documents 1 and 2 are known as such propylene-ethylene resincompositions for medical use.

Patent Document 1 describes a medical propylene-ethylene resincomposition comprising a propylene-ethylene copolymer (A) by aZiegler-catalyst system having an ethylene content of 0.1 to 3% byweight and a melt flow rate (MFR) conforming to JIS K7210 (230° C., 2.16kg load) of 10 to 300 g/10-min, and a propylene-ethylene copolymer (B)by a Ziegler-catalyst system having an ethylene content of 5 to 20% byweight and an MFR of 1 to 50 g/10-min, wherein the weight ratio of thepropylene-ethylene copolymer (A) to the propylene-ethylene copolymer (B)is 90:10 to 60:40, and the ethylene content of the medicalpropylene-ethylene resin composition is 2 to 8% by weight and an MFR of20 to 100 g/10-min (claim 1 of Patent Gazette). The weight ratio of(A):(B) in the examples is 67:33 to 74:26, and the content of (B) isrelatively large.

Patent Document 2 describes a medical propylene-ethylene resincomposition comprising 51 to 99 parts by weight of apropylene-ethylene-based resin composition (A) that includes 90 to 60%by weight of a propylene-ethylene copolymer (a) having an ethylenecontent of 0.1 to 3% by weight, and a melt flow rate (MFR) conforming toJIS K7210 (230° C., 2.16 kg load) is 10 to 300 g/10-min, and 10 to 40%by weight of a propylene-ethylene copolymer (b) having an ethylenecontent of 5 to 20% by weight and an MFR of 1 to 50 g/10-min, and thatthe propylene-ethylene resin composition (A) has total ethylene contentof 2 to 8% by weight and an MFR of 10 to 100 g/10-min (however, thetotal of (a) and (b) is 100% by weight), and 1 to 49 parts by weight ofan elastomer (B) (however, the total of (A) and (B) is 100 parts byweight) (claim 1 of Patent Gazette). The ratio (a):(b) in thepropylene-ethylene resin composition (A) in the examples is 67:33 to72:28, and the content of (b) is relatively large.

PRIOR ART DOCUMENTS Patent Document

-   Patent Document 1: JP 2015-44979 A (JP 6390231 B)-   Patent Document 2: JP 2015-193791 A (JP 6497090 B)

SUMMARY OF INVENTION Problems to be Solved by the Invention

Conventionally, a balance between transparency and impact resistance ofa propylene-based resin composition has been ensured by blending a largeamount of polymerized rubber or polyethylene (PE) component. However,there is a problem that the rigidity of the obtained propylene-basedresin composition is lowered by blending a large amount of theseblending components. Further, the decrease in rigidity causes a decreasein productivity, particularly a decrease in high-speed moldability ininjection molding.

On the other hand, a composition having an excellent balance oftransparency, impact resistance and rigidity by reducing the amount ofpolymerized rubber or PE component is not known. In particular, there isa strong demand for resin compositions suitable for medicalapplications, which are excellent in impact resistance and low elutionafter radiation sterilization.

In the present invention, by optimizing the composition of thepropylene-based resin composition and the polymerized rubber or PEcomponent to be blended, the targets of impact resistance andtransparency can be achieved, and the rigidity and productivity can beimproved. It is an object of the present invention to provide aninjection-molded article for medical use using the improvedpropylene-based resin composition.

Means for Dissolving the Problems

The present invention includes the following aspects [1] to [3]:

[1] An injection-molded article for medical use that has been sterilizedby g-ray or electron beam, wherein the injection-molded article obtainedby using a medical propylene-ethylene-based resin composition including88 to 95 parts by mass of a propylene-ethylene resin composition (A)that contains more than 90% by mass and equal to less than 97% by massof a propylene-ethylene copolymer (a) having an ethylene content of 1 to5% by mass, and a melt flow rate (hereinafter, abbreviated as MFR)conforming to JIS K7210 (230° C., 2.16 kg load) being 10 to 100g/10-min, and equal to more than 3% by mass and less than 10% by mass ofa propylene-ethylene copolymer (b) having an ethylene content of 15 to22% by mass and an MFR of 1 to 50 g/10-min, (with the proviso that thetotal of (a) and (b) is 100% by mass), and 5 to 12 parts by mass of anelastomer (B) that is an ethylene-α-olefin random copolymer which is anethylene-α-olefin random copolymer having a density of 0.880 to 0.920g/cm³ (with the proviso that the total of (A) and (B) being 100 parts bymass); and 0.01 to 0.20 parts by mass of a weather-resistant stabilizer.[2] The injection-molded article for medical use according to [1],wherein the elastomer (B) is an ethylene-α-olefin random copolymerpolymerized using a metallocene catalyst and having an MFR of 1 to 100g/10 min in accordance with JIS K7210 (190° C., 2.16 kg load).[3] The injection-molded article for medical use according to [1] or[2], wherein the medical propylene-ethylene-based resin compositionfurther includes a nucleating agent

Effect of the Invention

The present invention can provide a propylene-ethylene-based resincomposition capable of achieving the targets of impact resistance andtransparency and improving rigidity and productivity even if the contentof the propylene-ethylene copolymer (b) is lower than prior art. Canprovide things. Further, this resin composition is suitable as aninjection-molded article for medical use in which radiationsterilization is performed.

EMBODIMENTS OF THE INVENTION

Hereinafter, embodiments of the present invention will be described indetail, but these descriptions are examples of embodiments of thepresent invention, and the present invention is not limited to thesecontents.

[Propylene-Ethylene Copolymer (a)]

The propylene-ethylene copolymer (a) used in the present inventionsatisfies the following features 1a and 2a:

(Feature 1a: MFR)

The MFR of the propylene-ethylene copolymer (a) used in the presentinvention needs to be in the range of 10 to 100 g/10-min, preferably 20to 60 g/10-min, more preferably. 20 to 40 g/10-min. When it is equal toor more than the lower limit of this range, the molding processabilityis improved due to the improvement of the fluidity. Particularly, evenwhen the molded article having a wall thickness of 2.5 mm or less ismolded, the molding orientation is difficult to be applied, and when animpact is applied to the molded article, it is possible to preventcracks from occurring in the molding orientation direction. On the otherhand, when the copolymer (a) having the MFR equal to or less than theupper limit, the productivity of the resin composition is good andeconomically preferable, and the impact resistance of the molded articleafter radiation sterilization is excellent.

The method of controlling the MFR value is well known, and it can beeasily adjusted by adjusting the temperature and pressure which are thepolymerization conditions and controlling the amount of hydrogenationadded at the time of polymerization by a chain transfer agent such ashydrogen.

In the present invention, the MFR of the propylene-based resin ismeasured according to the A method and condition M (230° C., 2.16 kgload) of JIS K7210: 1999 “Plastic-Test method for melt mass-flow rate(MFR) and melt volume-flow rate (MVR) of thermoplastics”, and its unitis g/10-min. Further, a method of adjusting MFR by CR (control rheology)of MFR using a molecular weight adjusting agent is generally known, butin the present invention, it is preferable to adjust MFR only bypolymerization conditions without CR from the viewpoint of preventingthe resin from burning of the resin derived from the elastomer at thetime of molding.

(Feature 2a: Ethylene Content)

The ethylene content of the propylene-ethylene copolymer (a) used in thepresent invention needs to be in the range of 1 to 5% by mass,preferably 1.5 to 3.0% by mass. When the content is equal to or morethan the lower limit of this range, the transparency of the moldedarticle is good and the impact resistance after radiation sterilizationis excellent.

Further, when the content is not more than the upper limit value of thisrange, the solidification at the time of molding becomes faster due tothe increase of the crystallization temperature, and the moldingprocessability becomes good. The ethylene content can be adjusted bycontrolling the monomer composition of propylene and ethylene at thetime of polymerization.

[Propylene-Ethylene Copolymer (b)]

The propylene-ethylene copolymer (b) used in the present inventionsatisfies the following features 1b and 2b:

(Feature 1 b: MFR)

The MFR of the propylene-ethylene copolymer (b) used in the presentinvention needs to be in the range of 1 to 50 g/10-min, preferably 1 to30 g/10-min, more preferably 1 to 20 g/10-min, most preferably 1 to 10g/10-min. When the MFR is not less than the lower limit of this range,the dispersibility in the propylene-ethylene copolymer (a) is improved,and it is possible to suppress the generation of fish eyes in the moldedarticle. Further, when it is not more than the upper limit value, thelow crystal component is less likely to bleed on the surface, so thatthe drug adsorption property becomes good and the impact resistanceafter radiation sterilization becomes good. Further, although a methodof adjusting MFR by CR (control rheology) of MFR using a molecularweight adjusting agent is generally known, in the present invention, itis preferable to adjust MFR only by polymerization conditions without CRfrom the viewpoint of preventing the resin from burning of the resinderived from the elastomer at the time of molding.

(Feature 2b: Ethylene Content)

The ethylene content of the propylene-ethylene copolymer (b) used in thepresent invention needs to be in the range of 15 to 22% by mass,preferably 15 to 21% by mass, more preferably 15 to 19% by mass, andfurther preferably 17 to 19% by mass. When it is not less than the lowerlimit value of this range, the impact resistance of the molded articleafter radiation sterilization is improved. When the value is not morethan the upper limit value, the compatibility with thepropylene-ethylene copolymer (a) is improved, so that the transparencyof the molded article is improved, as well as the propylene-ethylenecopolymer (b) is hardly to bleed on the surface of the molded article,so that stickiness and drug adsorption are improved.

[Propylene-Ethylene Resin Composition (A)]

As the mass ratio of the propylene-ethylene copolymer (a) to thepropylene-ethylene copolymer (b) used in the present invention, it isnecessary to contain the propylene-ethylene copolymer (a) with more than90% by mass and equal to less than 97% by mass and thepropylene-ethylene copolymer (b) with the range of 3% by mass or moreand less than 10% by mass. Preferably, the mass ratio of thepropylene-ethylene copolymer (a) is 91% by mass to 95% by mass, and themass ratio of the propylene-ethylene copolymer (b) is 5% by mass to 9%by mass. When the lower limit of the mass ratio of thepropylene-ethylene copolymer (a) is more than 90% by mass, the rigidityof the molded article and the light transmittance in water are improved,and when it is the upper limit of 97% by mass or less, the moldedarticle is excellent in impact resistance.

The ratios of the propylene-ethylene copolymers (a) and (b) in thepropylene-ethylene resin composition (A) are values obtained from thematerial balance at the time of polymerization in the case of continuouspolymerization. When manufactured by blending, it is a value obtainedfrom each composition ratio.

Further, each ethylene content is a value measured by using the ¹³C-NMRmethod.

The method for producing the propylene-ethylene copolymer (a) and thepropylene-ethylene copolymer (b) used in the present invention is notparticularly limited, and may be obtained by copolymerizing propyleneand ethylene in the presence of a metallocene compound-containingcatalyst or a Ziegler-Natta catalyst.

Regarding the production process of the propylene-ethylene copolymer (a)and the propylene-ethylene copolymer (b), any method may be used as longas the above-mentioned characteristics are satisfied. Regarding themixing of the propylene-ethylene copolymer (a) and thepropylene-ethylene copolymer (b), it may be produced by any method aslong as the above-mentioned characteristics are satisfied.

[Elastomer (B)]

The propylene-ethylene resin composition of the present inventionincludes an elastomer (B) which is an ethylene-α-olefin random copolymerhaving a density of 0.880 to 0.920 g/cm³. The elastomer (B) ispreferably an ethylene-α-olefin random copolymer polymerized using ametallocene catalyst and having an MFR of 1 to 100 g/10 min according toJIS K7210 (190° C., 2.16 kg load). The elastomer (B) may be used aloneor in combination of two or more thereof.

The content ratio of the propylene-ethylene resin composition (A) andthe elastomer (B) is 88 to 95 parts by mass for the propylene-ethyleneresin composition (A) and 5 to 12 parts by mass for the elastomer (B).The propylene-ethylene resin composition (A) is dispersed in a smallamount of the elastomer (B). The propylene-ethylene resin composition(A) is preferably 90 to 95 parts by mass, and the elastomer (B) ispreferably 5 to 10 parts by mass. Within this range, the resincomposition has excellent high-speed moldability and impact resistanceafter irradiation.

The ethylene-α-olefin random copolymer is a random copolymer elastomerof ethylene and an α-olefin having 3 or more and 20 or less carbonatoms. Specific examples of the α-olefin having 3 or more and 20 or lesscarbon atoms include propylene, 1-butene, 1-pentene, 1-hexene,4-methyl-1-pentene, 1-heptene, 1-octene, 1-decene, 1-dodecene,1-tetradecene, 1-hexadecene, 1-eikosen and the like.

These α-olefins can be used alone or in combination. Among these,propylene, 1-butene, 1-hexene and 1-octene are particularly preferablyused. Further, when α-olefins are used in combination, it is preferableto combine propylene and 1-butene. The details of the ethylene-α-olefinrandom copolymer and the ethylene-propylene-butene random copolymer aredescribed below.

[Ethylene-α-Olefin Random Copolymer]

Among the elastomers (B) used in the present invention, the morphologyof the material is changed by containing a specific amount of theethylene-α-olefin random copolymer, and impact resistance can be furtherimproved while maintaining properties of the transparency, low odor,rigidity and low foreign matter appearance.

Such an ethylene-α-olefin random copolymer is an ethylene-α-olefinrandom copolymer having a density of 0.880 to 0.920 g/cm³, preferably0.880 to 0.915 g/cm³. Examples of α-olefins include propane, 1-butene,1-pentene, 1-hexene, 4-methyl-1-pentene, 3-methyl-1-pentene, 1-heptene,1-octene, 1-decene and the like.

Specific examples of the ethylene-α-olefin random copolymers includeethylene-propylene random copolymer, ethylene-1-butene random copolymer,ethylene-1-pentene random copolymer, ethylene-1-hexen random copolymer,ethylene-4-methyl-1-pentene random copolymer,ethylene-3-methyl-1-pentene random copolymer, ethylene-1-hepten randomcopolymer, ethylene-1-octene random copolymer and ethylene-1-decenerandom copolymer.

The ethylene-α-olefin random copolymer can be used those having glasstransition temperature (Tg) of −130° C. to −20° C., but the Tg isgenerally considerably lower than that of a propylene-based polymer, soattempts have been made to blend the copolymer into the propylene-basedpolymer to improve the impact resistance after irradiation whilemaintaining transparency, but the results did not exceed expectations.However, the combined use of the propylene-ethylene resin composition(A) and the elastomer (B) of the present invention can be expected tohave an excellent effect.

The melt flow rate according to JIS K7210 (190° C., 2.16 kg load)(hereinafter it may be abbreviated as MFR (190° C.)) of theethylene-α-olefin random copolymer is preferably 1 to 60 g/10-min, morepreferably 2 to 40 g/10-min. Within this range, the mixed state of thepropylene-ethylene resin composition (A) constituting the medicalpropylene-ethylene resin composition and the ethylene-α-olefin randomcopolymer (elastomer (B)) is good. Therefore, it is possible to stablyobtain a medical propylene-ethylene resin composition having excellenttransparency and a good balance of physical properties.

When the propylene-ethylene resin composition (A) and theethylene-α-olefin random copolymer are mixed, the smaller the MFRdifference between the propylene-ethylene resin composition (A) and theethylene-α-olefin random copolymer, the more the ethylene-α-olefinrandom copolymer tends to exist as a slightly dispersed domain in thepropylene-ethylene resin composition (A), which is desirable because thetransparency is improved.

Specifically, the MFR ratio expressed by MFR (190° C.) of theethylene-α-olefin random copolymer/MFR of propylene-ethylene resincomposition (A) is preferably 0.05 to 1.2, more preferably 0.1 to 1.0.It is expected that this range is also significant in order to properlyexhibit the functions of the present invention as a medical moldedarticle, such as transparency, contamination with foreign substances,and prevention of odor.

The density of the ethylene-α-olefin random copolymer is preferably0.880 to 0.920 g/cm³, more preferably 0.880 to 0.915 g/cm³. When anethylene-α-olefin random copolymer is blended with thepropylene-ethylene resin composition (A), the transparency may bedeteriorated. However, if the ethylene-α-olefin random copolymer havingthe smaller density difference from the propylene-ethylene resincomposition (A) and the MFR ratio expressed by MFR (190° C.) of theethylene-α-olefin random copolymer/MFR of propylene-ethylene resincomposition (A) that is close to 0.5 is used, the tendency ofdeterioration of transparency can be alleviated and the impactresistance can be improved. Here, the density is a value measuredaccording to JIS K7112.

Such an ethylene-α-olefin random copolymer can be produced by using acatalyst for a stereoregular polymerization of olefins and polymerizingin the coexistence of ethylene and α-olefin while adjusting themolecular weight. Specifically, the ethylene-α-olefin random copolymercan be produced by reacting ethylene with α-olefin such as propylene,1-butene, 1-hexene, 4-methyl-1-pentene and 1-oxtene, using a catalystsuch as a Ziegler catalyst, a Phillips catalyst, or a metallocenecatalyst as the catalyst for the stereoregular polymerization ofolefins, by the process such as a gas phase method, a solution method, ahigh-pressure method, and slurry method. In particular, in order toreduce the Mw/Mn and the density, the ethylene-α-olefin random copolymeris desirably produced by using the metallocene catalyst as the catalystfor the stereoregular polymerization of olefins and in the high-pressuremethod or the solution method.

Further, the ethylene-α-olefin random copolymer selectively used in themedical propylene-ethylene resin composition of the present invention isused alone or in combination of two or more as long as the effect of thepresent invention is not impaired. can do.

Such ethylene-α-olefin random copolymers are commercially availableproducts such as NOVATEC™ LL series and HARMOREX™ series manufactured byNippon Polyethylene Corporation, KERNEL™ series, and TOUGHMER™ P seriesand TOUGHMER™ A series manufactured by Mitsui Chemicals Inc., EVOLUE™series manufactured by Prime Polymer Co., Ltd., SUMIKATHENE™ E, EPseries, and EXCELLEN™ GMH series manufactured by Sumitomo Chemicals Co.,Ltd. can be exemplified.

As ethylene-α-olefin random copolymers polymerized using a metallocenecatalyst, HARMOREX™ series and kernel series manufactured by NipponPolyethylene Corporation, EVOLUE™ series manufactured by Prime PolymerCo., Ltd., and EXCELLEN™ FX series manufactured by Sumitomo ChemicalCo., Ltd., and the like can be exemplified.

In the medical propylene-ethylene propylene-based resin composition ofthe present invention, the content ratio when the ethylene-α-olefinrandom copolymer as the elastomer (B) is blended into thepropylene-ethylene resin composition (A) is 88 to 95 parts by mass forthe ethylene-based resin composition (A), and 5 to 12 part by mass forthe ethylene-α-olefin random copolymer, and preferably 90 to 95 parts bymass for the propylene-ethylene resin composition (A) and 5 to 10 partsby mass for the ethylene-α-olefin random copolymer. Within this range,the resin composition has excellent impact resistance after irradiation.

[Nucleating Agent]

When the medical propylene-ethylene resin composition of the presentinvention contains a nucleating agent, a molded article having bettertransparency can be obtained. The nucleating agent is not particularlylimited, but a sorbitol-based nucleating agent, a phosphorus-basednucleating agent, a carboxylic acid metal salt-based nucleating agent, apolymer nucleating agent, an inorganic compound and the like can beused. As the nucleating agent, it is preferable to use thesorbitol-based nucleating agent, the phosphorus-based nucleating agent,or the polymer nucleating agent.

As the sorbitol-based nucleating agent, for example, nonitol1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene] (commerciallyavailable product containing this compound, trade name “Mirrored NX8000series, manufactured by Milliken (“NX8000” is the above chemicalsubstance+fluorescent whitening agent+blooming agent, “NX8000K” is“NX8000” without fluorescent whitening agent, “NX8000J” is “NX8000”without fluorescent whitening agent and blooming (Without both agents)),1,3,2,4-dibenzylidene sorbitol, 1,3,2,4-di-(p-methylbenzylidene)sorbitol, 1,3-p-chlorobenzylidene-2,4-p-methylbenzylidene sorbitol canbe used.

Examples of the phosphorus-based nucleating agent includesodium-bis-(4-t-butylphenyl) phosphate, potassium-bis-(4-t-butylphenyl)phosphate, and sodium-2,2′-ethylidene-bis-(4,6-di-t-butylphenyl)phosphate, sodium-2,2′-methylene-bis-(4,6-di-t-butylphenyl) phosphate,bis(2,4,8,10-tetra-t-butyl hydroxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin-6-oxide) sodium salt (trade name “ADK STABNA-11”, manufactured by ADEKA CORPORATION), composite product ofbis(2,4,8,10-tetra-t-butyl-6-hydroxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin-6-oxide) aluminum hydroxide salt as a maincomponent (trade name “ADK STAB NA-21”, manufactured by ADEKACORPORATION), lithium-2,2′-methylene-bis (4,6-di-t-butylphenyl)phosphate and 12-hydroxystearic acid. A composite containing andcontaining lithium as an essential component (trade name “ADK STABNA-71”, manufactured by ADEKA CORPORATION) or the like can be used.

As the carboxylic acid metal salt nucleating agent, for example,p-t-butyl benzoic acid aluminum salt, aluminum adipate, and sodiumbenzoate can be used.

Branched α-olefin polymers are preferably used as the polymer nucleatingagent.

Examples of the branched α-olefin polymers include homopolymers, or of3-methyl-1-butene, 3-methyl-1-pentene, 3-ethyl-1-pentene,4-methyl-1-pentene, 4-methyl-1-hexene, 4,4-dimethyl-1-hexene,4,4-dimethyl-1-pentene, 4-ethyl-1-hexene, 3-ethyl-1-hexene, orcopolymers thereof and further copolymers of them with other α-olefins.A polymer of 3-methyl-1-butene is particularly preferable from theviewpoints of good transparency, low-temperature impact resistance,rigidity, and economic efficiency.

As the inorganic compound, for example, talc, mica, and calciumcarbonate can be used.

As described above, some of the nucleating agents used in the presentinvention can be easily obtained as commercial products.

Among these nucleating agents, nonitol1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl)methylene] and/orbis(2,4,8,10-tetra-t-butyl-6-hydroxy-12H-dibenzo[d,g][1,3,2]dioxaphosphocin-6-oxide) aluminum hydroxide salt are preferableto use from the viewpoint of transparency, low temperature impactresistance, rigidity and low odor.

Further, these nucleating agents may be used alone or in combination oftwo or more.

[Weather-Resistant Stabilizer]

The medical propylene-ethylene resin composition of the presentinvention contains a weather-resistant stabilizer.

Specific examples of the weather-resistant stabilizer includephosphorus-based antioxidants such as bis(2,6-di-t-butyl-4-methylphenyl)pentaerythritol-di-phosphite, di-stearyl-pentaerythritol-di-phosphite,and bis(2,4-di-t-butylphenyl) pentaerythritol-di-phosphite, tris(2,4-di-t-butylphenyl) phosphite,tetrakis(2,4-di-t-butylphenyl)-4,4′-biphenylene-di-phosphonite,tetrakis(2,4-di-t-butyl-5-methyl-phenyl)-4,4′-biphenylene-di-phosphonite;n-hexadecyl-3,5-di-t-butyl-4-hydroxy-benzoate,2,4-di-t-butylphenyl-3′,5′-di-t-butyl-4′-hydroxybenzoate,bis(2,2,6,6-tetramethyl-4-piperidyl) sevacate, ethanol condensate ofdimethyl-2-(4-hydroxy-2,2,6,6-tetramethyl-1-piperidyl) succinate;hindered amine-based stabilizers such aspoly{[6-[(1,1,3,3-tetramethylbutyl)amino]-1,3,5-triazine-2,4-diyl][(2,2,6,6-tetramethyl-4-piperidyl)imino]hexamethylene[(2,2,6,6-tetramethyl-4-piperidyl)-imino]}, and N,N′-bis(3-aminopropyl)ethylenediamine-2,4-bis[N-butyl-N-(1,2,2,6,6-pentamethyl-4-piperidyl)amino]-6-chloro-1,3,5-triazinecondensate; phenol-based antioxidants such as 2,6-di-t-butyl-p-cresol,tetrakis[methylene-(3,5-di-t-butyl-4-hydroxyhydrocinnamate)]methane,1,3,5-trimethyl-2,4,6-tris-(3,5-di-t-butyl-4-hydroxybenzyl) benzene, andtris(3,5-di-t-butyl-4-hydroxybenzyl) isocyanurate; thio-basedantioxidants such as di-stearyl-β, β′-thio-di Examples thereof includepropionate, di-myristyl-β,β′-thio-di-propionate,di-lauryl-β,β′-thio-di-propionate.

Incidentally, the weather-resistant stabilizer may be used singly or incombination of a plurality of them, the propylene-ethylene resincomposition according to the present invention is preferably blendedwith phosphorus-based antioxidants or hindered amine-based stabilizersfrom the view point of color change after sterilization because it isused for an injection-molded article for medical use to be sterilized byradiation. Among the phosphorus-based antioxidants,tris(2,4-di-t-butylphenyl) phosphite is particularly preferable becauseit has an excellent balance between suppressing resin deterioration anddiscoloration during radiation sterilization. Among the hinderedamine-based stabilizers, high-molecular-weight hindered amine-basedstabilizers are preferable from the viewpoint of low elution, andethanol condensate ofdimethyl-2-(4-hydroxy-2,2,6,6-tetramethyl-1-piperidyl) succinate isparticularly preferable because it has an excellent in balance ofsuppression of resin deterioration during radiation sterilization,long-term stability of the molded article after sterilization, anddiscoloration, and low elution. In addition, among the hinderedamine-based stabilizers, the basicity of this compound is a weak andclose to neutral, so that it has little effect on the content liquid andis preferable. It is most preferable to use a phosphorus-basedantioxidant and a hindered amine-based antioxidant in combination fromthe viewpoint of suppressing resin deterioration during radiationsterilization and maintaining the long-term stability of the moldedarticle after sterilization.

Further, in the medical propylene-ethylene resin composition of thepresent invention, amine-based antioxidants represented by the followingformulae (3) and (4) which is no discoloration by radiation treatment,and excellent in a NOx gas discoloration resistance, lactone-basedantioxidants such as5,7-di-t-butyl-3-(3,4-di-methyl-phenyl)-3H-benzofuran-2-one, and vitaminE-based antioxidants such as the following general formula (5) may beblended as long as the effect of the present invention can be obtained.

The blending amount of the weather resistance stabilizer is 0.01 to 0.20mass with respect to 100 parts by mass of the medical propylene-ethyleneresin composition. It is preferably 0.02 to 0.10 parts by mass. When itis 0.01 parts by mass or more, the effect as a weather-resistantstabilizer is sufficiently exhibited, and when it is 0.20 parts by massor less, there is no adverse effect on transparency and the like.

[Other Additives]

Further, the medical propylene-ethylene resin composition of the presentinvention can contain other agents such as known copper damageinhibitors, ultraviolet absorbers, antistatic agents, hydrophilicagents, slip agents, anti-blocking agents, anti-fogging agents,colorants, fillers, petroleum resins, antibacterial agents and the likewithin the range not impaired in its performance.

[Method for Producing Medical Propylene-Ethylene Resin Composition]

The medical propylene-ethylene resin composition of the presentinvention is obtained by blending predetermined amount of variouscompounding components such as the above-mentioned propylene-ethylenecopolymer (a), propylene-ethylene copolymer (b), elastomer (B),nucleating agent, neutralizing agent, lubricant, antioxidant, and otheradditives, by using a normal mixing device such as Henshell mixer (tradename), super mixer, ribbon blender, tumbler mixer, Banbury mixer. Theresulting mixture can be made into a pellet-like composition by meltneedling and pelletizing using a single screw extruder, a twin-screwextruder, a Banbury mixer, a plastic bender, a roll, or the like, at amelt-kneading temperature of 150 to 300° C., preferably 180 to 250° C.

[Molded Article]

The molded article of the present invention is an injection-moldedarticle for medical use obtained by molding the above-mentioned medicalpropylene-ethylene resin composition by a known injection moldingmachine.

Since the resin composition of the present invention is excellent inmolding processability at the time of injection molding, aninjection-molded article with high accuracy can be obtained in a shortmolding cycle. The obtained injection-molded articles are used for awide variety of medical applications, and specific molded articlesinclude medical instruments and containers (disposable instruments suchas disposable syringes and their parts, catheters/tubes, infusion bags,blood bags, vacuum blood collection tubes, non-woven fabrics forsurgery, blood filters, blood circuits; parts of artificial organs suchas artificial lungs and artificial anal; dialyzer, prefilled syringe,kit formulation, drug container, test tube, suture, base material ofpoultice, parts of dental material, parts of orthopedic material,contact lens cases, contact lens molds, PTP, SP/sachets, P vials, eyemedicine containers, chemical liquid containers, long-term liquidstorage containers, etc.), medical containers (infusion packs), anddaily necessities (clothes cases, buckets, washbasins, writing utensils,etc.).

Since the molded article of the present invention is for medical use, itcan be often sterilized, and examples of the sterility method includegas sterility (EOG), high-pressure steam sterility, and radiationsterility (γ-ray, electron beam). In particular, the molded articleobtained by using this resin composition is suitable for radiationsterilization and has excellent impact resistance even after radiationsterilization. The radiation sterilization dose suitable for the presentmolded article is preferably 1 kGy to 100 kGy, and more preferably 10kGy to 60 kGy. Depending on the product, sterilization can be performedwhen the dose is above the lower limit, and when the dose is below theupper limit, the balance between sterility, impact resistance and lowelution after sterilization is excellent.

Further, from the viewpoint of transparency, the molded article usingthe present resin composition preferably has an average wall thicknessof 3.0 mm or less, more preferably 2.5 mm or less, and furtherpreferably 2.0 mm or less, particularly preferably 1.5 mm, moreparticularly preferably 1.2 mm or less, and most preferably 1.0 mm orless. Sufficient transparency is exhibited when the thickness is notmore than the upper limit. Further, the average wall thickness of themolded article herein referred means to the wall thickness of the widestpart as a percentage of the total surface area of the molded article. Asa typical example, in a syringe (syringe or tubular part is called abarrel), it refers to the wall thickness of the cylindrical part of theouter cylinder (barrel).

Further, the present resin composition can provide an injection-moldedarticle having a good balance between product rigidity and impactresistance. In addition, the present resin composition is suitable forartificial dialysis members because of satisfying the heavy metal test,lead test, cadmium test, and eluent test described in Yakuhatsu No. 494Dialysis Artificial Kidney Device Approval Criteria, IV Blood CircuitQuality and Test Method after radiation sterility. Especially, thepresent resin composition is suitable for dialyzer housings and headers,and related members. Furthermore, the present resin composition issuitable for syringe members in order to satisfy the 6 chemicalrequirements described in JIS T3210: 2011 sterilized syringes, andespecially suitable for disposable syringes.

EXAMPLES

Hereinafter, the present invention will be specifically described withreference to Examples, but the present invention is not limited to theseExamples. In the following, the propylene-ethylene copolymers (a) and(b) are described as “PP component (a)” and “PP component (b)”, and thepropylene-ethylene resin composition may be described as“propylene-based polymer”.

<Production Example of Propylene-Based Polymer (A-1)> (1) Preparation ofSolid Catalyst Component

95.2 g of anhydrous magnesium chloride, 442 mL of decane and 390.6 g of2-ethylhexyl alcohol were heated and reacted at 130° C. for 2 hours toprepare a uniform solution. Thereafter, 21.3 g of phthalic anhydride wasadded to this solution, and the mixture was further stirred and mixed at130° C. for 1 hour to dissolve phthalic anhydride.

After cooling the uniform solution thus obtained to room temperature, 75mL of this uniform solution was added dropwise over 200 mL of titaniumtetrachloride kept at −20° C. for 1 hour. After the charging iscompleted, the temperature of this mixed solution was raised to 110° C.over 4 hours, 5.22 g of diisobutyl phthalate (DIBP) was added when thetemperature reached 110° C., and the mixture was stirred and kept at thesame temperature for 2 hours.

After the reaction for 2 hours was completed, the solid part wascollected by hot filtration, the solid part was resuspended in 275 mL oftitanium tetrachloride, and then heated again at 110° C. for 2 hours.After completion of the reaction, the solid part was collected again byhot filtration and washed thoroughly with decane and hexane at 110° C.until no free titanium compound was detected in the solution.

Here, the detection of the free titanium compound was confirmed by thefollowing method. 10 mL of the supernatant liquid of the above solidcatalyst component was collected with a syringe and charged into 100 mLof Schlenk with a branch that the inside had been replaced with nitrogenin advance. Next, the solvent hexane was dried in a nitrogen stream andvacuum dried for another 30 minutes. 40 mL of ion-exchanged water and 10mL of 50% by volume sulfuric acid were charged therein and stirred for30 minutes. This aqueous solution was transferred through a filter paperto a 100-mL volumetric flask, followed by 1 mL of conc. H₃PO₄ as amasking agent for iron (II) ions and 5 mL of 3% H₂O₂ aqueous solution asa color-developing reagent for titanium were added, and the volume wasfurther increased to 100 mL with ion-exchanged water. This measuringflask was shaken, and after 20 minutes, the absorbance at 420 nm wasobserved using UV to detect free titanium.

The washing and removal of the free titanium and the detection of thefree titanium was repeated until the absorbance was no longer observed.

The solid titanium catalyst component (A) prepared as described abovewas stored as a decane slurry, and a part of the solid titanium catalystcomponent (A) was dried for examining the catalyst composition. Thecomposition of the solid titanium catalyst component (A) thus obtainedwas 2.3% by mass of titanium, 61% by mass of chlorine, 19% by mass ofmagnesium, and 12.5% by mass of DIBP.

(2) Preparation of Catalyst Component for Pre-Polymerization:

After the inside of a three-necked flask with a stirrer and an internalvolume of 500 mL was replaced with nitrogen gas, 400 mL of dehydratedheptane, 19.2 mmol of triethylaluminum, 3.8 mmol ofdicyclopentyldimethoxysilane, and 4 g of the above solid titaniumcatalyst component (A) were charged. The internal temperature of theflask was maintained at 20° C., and propylene was introduced whilestirring. After 1 hour, stirring was stopped, and as a result, apre-polymerization catalyst component (B) in which 2 g of propylene waspolymerized per 1 g of the solid titanium catalyst component (A) wasobtained.

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with stirrer and having an internalvolume of 10 L was sufficiently dried, and after nitrogen substitution,6 L of dehydrated heptane, 12.5 mmol of triethyl aluminum, and 0.6 mmolof dicyclopentyl dimethoxysilane. were charged. After replacing thenitrogen in the system with propylene, hydrogen was charged at 0.15MPa-G, and then propylene and ethylene were introduced with stirring.The introduction amount was adjusted so that the ethylene concentrationin the gas phase portion in the polymerization tank was 1.4 mol %.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the pre-polymerization catalyst component (B) with 0.10 mmolin terms of Ti atoms was added. The polymerization was carried out at80° C. for 3 hours while propylene was continuously supplied.

The MFR of the PP component (a) was 45 g/10-min, and the ethylenecontent was 1.8% by mass.

(3-2) Polymerization-2 (Polymerization [Step 2])

After the polymerization of the PP component (a) was completed (afterthe above [Step 1]), the internal temperature was lowered to 30° C. anddepressurized. Then, hydrogen was charged at 0.94 MPa-G, and then amixed gas of propylene/ethylene: (4.3 L/min)/(1.1 L/min) was introduced.Propylene/ethylene copolymerization was carried out for 50 minutes at aninternal temperature of 60° C. and a total pressure of 0.30 MPa-G(varies depending on the amount of introduced gas).

After a predetermined amount of time had elapsed, 50 mL of methanol wasadded to stop the reaction, and the temperature was lowered anddepressurized. The entire contents were transferred to a filtration tankequipped with a filter, heated to 60° C., and subjected to solid-liquidseparation. Further, the solid portion was washed twice with 6 L ofheptane at 60° C. The propylene/ethylene copolymer thus obtained wasvacuum dried.

When the index for the PP component (b) produced in the second stage wascalculated, the production amount was 7% by mass based on the totalweight, the MFR was 7.0 g/10-min, and the ethylene content was 18.0% bymass.

<Manufacturing of Propylene-Based Polymer (A-2)>

The steps (1) and (2) are the same as those of the propylene-basedpolymer (A-1).

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with a stirrer and having aninternal volume of 10 L was sufficiently dried, and after nitrogensubstitution, 6 L of dehydrated heptane, 12.5 mmol of triethylaluminum,0.6 mmol of dicyclopentyldimethoxysilane. were charged. After replacingthe nitrogen in the system with propylene, hydrogen was charged at 0.15MPa-G, and then propylene and ethylene were introduced with stirring themixture. The introduction amount was adjusted so that the ethyleneconcentration in the gas phase portion in the polymerization tank was1.4 mol %.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure at 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the above pre-polymerization catalyst component (B) with 0.10mmol in terms of Ti atoms was added. The polymerization was carried outat 80° C. for 3 hours while propylene was continuously supplied.

The MFR of the PP component (a) was 45 g/10-min, and the ethylenecontent was 1.8% by mass.

(3-2) Polymerization-2 (Polymerization [Step 2])

After the polymerization of the PP component (a) was completed (afterthe above [Step 1]), the internal temperature was lowered to 30° C. anddepressurized. Then, hydrogen was charged at 0.90 MPa-G, and then amixed gas of propylene/ethylene: (4.2 L/min)/(1.2 L/min) was introduced.Propylene/ethylene copolymerization was carried out for 50 minutes at aninternal temperature of 60° C. and a total pressure of 0.30 MPa-G(varies depending on the amount of introduced gas).

After a predetermined amount of time had elapsed, 50 mL of methanol wasadded to stop the reaction, and the temperature was lowered anddepressurized. The entire contents were transferred to a filtration tankequipped with a filter, heated to 60° C., and solid-liquid separated.Further, the solid portion was washed twice with 6 L of heptane at 60°C. Propylene/ethylene copolymer thus obtained was vacuum dried.

When the index for the PP component (b) produced in the second stage wascalculated, the production amount was 7% by mass based on the totalweight, the MFR was 3.0 g/10-min, and the ethylene content was 19.0% bymass.

<Manufacturing of Propylene-Based Polymer (A-3)>

The steps (1) and (2) are the same as those of the propylene-basedpolymer (A-1).

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with stirrer and having an internalvolume of 10 L was sufficiently dried, and after nitrogen substitution,6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, 0.6 mmol ofdicyclopentyl-dimethoxysilane. was added. After replacing the nitrogenin the system with propylene, hydrogen was charged at 0.15 MPa-G, andthen propylene and ethylene were introduced with stirring. Theintroduction amount was adjusted so that the ethylene concentration inthe gas phase portion in the polymerization tank was 1.4 mol %.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the pre-polymerization catalyst component (B) with 0.10 mmolin terms of Ti atoms was added. The polymerization was carried out at80° C. for 3 hours while propylene was continuously supplied.

The MFR of the PP component (a) was 45 g/10-min, and the ethylenecontent was 1.8% by mass.

(3-2) Polymerization-2 (Polymerization [Step 2])

After the polymerization of the PP component (a) was completed (afterthe above [Step 1]), the internal temperature was lowered to 30° C. anddepressurized. Then, hydrogen was charged at 0.92 MPa-G, and then amixed gas of propylene/ethylene: (4.0 L/min)/(1.4 L/min) was introduced.Propylene/ethylene copolymerization was carried out for 50 minutes at aninternal temperature of 60° C. and a total pressure of 0.30 MPa-G(varies depending on the amount of introduced gas).

After a predetermined amount of time had elapsed, 50 mL of methanol wasadded to stop the reaction, and the temperature was lowered anddepressurized. The entire contents were transferred to a filtration tankequipped with a filter, heated to 60° C., and solid-liquid separated.Further, the solid portion was washed twice with 6 L of heptane at 60°C. Propylene/ethylene copolymer thus obtained was vacuum dried.

When the index for the PP component (b) produced in the second stage wascalculated, the production amount was 7% by mass based on the totalweight, the MFR was 5.0 g/10-min, and the ethylene content was 21.0% bymass.

<Manufacturing of Propylene-Based Polymer (A-4)>

The steps (1) and (2) are the same as those of the propylene-basedpolymer (A-1).

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with stirrer and having an internalvolume of 10 L was sufficiently dried, and after nitrogen substitution,6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmolof dicyclo-pentyldimethoxysilane. was added. After replacing thenitrogen in the system with propylene, hydrogen was charged at 0.15MPa-G, and then propylene and ethylene were introduced with stirring.The introduction amount was adjusted so that the ethylene concentrationin the gas phase portion in the polymerization tank was 1.8 mol %.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the pre-polymerization catalyst component (B) with 0.10 mmolin terms of Ti atoms was added. The polymerization was carried out at80° C. for 3 hours while propylene was continuously supplied.

The MFR of the PP component (a) was 45 g/10-min, and the ethylenecontent was 2.3% by mass.

(3-2) Polymerization-2 (Polymerization [Step 2])

After the polymerization of the PP component (a) was completed (afterthe above [Step 1]), the internal temperature was lowered to 30° C. anddepressurized. Then, hydrogen was charged at 0.92 MPa-G, and then amixed gas of propylene/ethylene: (4.0 L/min)/(1.4 L/min) was introduced.Propylene/ethylene copolymerization was carried out for 50 minutes at aninternal temperature of 60° C. and a total pressure of 0.30 MPa-G(varies depending on the amount of introduced gas).

After a predetermined amount of time had elapsed, 50 mL of methanol wasadded to stop the reaction, and the temperature was lowered anddepressurized. The entire contents were transferred to a filtration tankequipped with a filter, heated to 60° C., and solid-liquid separated.Further, the solid portion was washed twice with 6 L of heptane at 60°C. The propylene/ethylene copolymer thus obtained was vacuum dried.

When the index for the PP component (b) produced in the second stage wascalculated, the production amount was 7% by mass based on the totalweight, the MFR was 5.0 g/10-min, and the ethylene content was 21.0% bymass.

<Manufacturing of Propylene-Based Polymer (A-5)>

The steps (1) and (2) are the same as those of the propylene-basedpolymer (A-1).

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with stirrer and having an internalvolume of 10 L was sufficiently dried, and after nitrogen substitution,6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmolof dicyclo-pentyldimethoxysilane. was added. After replacing thenitrogen in the system with propylene, hydrogen was charged at 0.15MPa-G, and then propylene and ethylene were introduced with stirring.The introduction amount was adjusted so that the ethylene concentrationin the gas phase portion in the polymerization tank was 2.3 mol %.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the pre-polymerization catalyst component (B) with 0.10 mmolin terms of Ti atoms was added. The polymerization was carried out at80° C. for 3 hours while propylene was continuously supplied.

The MFR of the PP component (a) was 45 g/10-min, and the ethylenecontent was 3.0% by mass.

(3-2) Polymerization-2 (Polymerization [Step 2])

After the polymerization of the PP component (a) was completed (afterthe above [Step 1]), the internal temperature was lowered to 30° C. anddepressurized. Then, hydrogen was charged at 0.92 MPa-G, and then amixed gas of propylene/ethylene: (4.0 L/min)/(1.4 L/min) was introduced.Propylene/ethylene copolymerization was carried out for 50 minutes at aninternal temperature of 60° C. and a total pressure of 0.30 MPa-G(varies depending on the amount of introduced gas).

After a predetermined amount of time had elapsed, 50 mL of methanol wasadded to stop the reaction, and the temperature was lowered anddepressurized. The entire contents were transferred to a filtration tankequipped with a filter, heated to 60° C., and solid-liquid separated.Further, the solid portion was washed twice with 6 L of heptane at 60°C. The propylene/ethylene copolymer thus obtained was vacuum dried.

When the index for the PP component (b) produced in the second stage wascalculated, the production amount was 7% by mass based on the totalweight, the MFR was 5.0 g/10-min, and the ethylene content was 21.0% bymass.

<Manufacturing of Propylene-Based Polymer (A-6)>

The steps (1) and (2) are the same as those of the propylene-basedpolymer (A-1).

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with stirrer and having an internalvolume of 10 L was sufficiently dried, and after nitrogen substitution,6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmolof dicyclo-pentyldimethoxysilane. was added. After replacing thenitrogen in the system with propylene, hydrogen was charged at 0.15MPa-G, and then propylene and ethylene were introduced with stirring.The introduction amount was adjusted so that the ethylene concentrationin the gas phase portion in the polymerization tank was 1.8 mol %.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the pre-polymerization catalyst component (B) with 0.10 mmolin terms of Ti atoms was added. The polymerization was carried out at80° C. for 3 hours while propylene was continuously supplied.

The MFR of the PP component (a) was 45 g/10-min, and the ethylenecontent was 2.3% by mass.

(3-2) Polymerization-2 (Polymerization [Step 2])

After the polymerization of the PP component (a) was completed (afterthe above [Step 1]), the internal temperature was lowered to 30° C. anddepressurized. Then, hydrogen was charged at 0.92 MPa-G, and then amixed gas of propylene/ethylene: (4.0 L/min)/(1.4 L/min) was introduced.Propylene/ethylene copolymerization was carried out for 40 minutes at aninternal temperature of 60° C. and a total pressure of 0.30 MPa-G(varies depending on the amount of introduced gas).

After a predetermined amount of time had elapsed, 50 mL of methanol wasadded to stop the reaction, and the temperature was lowered anddepressurized. The entire contents were transferred to a filtration tankequipped with a filter, heated to 60° C., and solid-liquid separated.Further, the solid portion was washed twice with 6 L of heptane at 60°C. The propylene/ethylene copolymer thus obtained was vacuum dried.

When the index for the PP component (b) produced in the second stage wascalculated, the production amount was 5% by mass based on the totalweight, the MFR was 5.0 g/10-min, and the ethylene content was 21.0% bymass.

<Manufacturing of Propylene-Based Polymer (A-7)>

The steps (1) and (2) are the same as those of the propylene-basedpolymer (A-1).

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with stirrer and having an internalvolume of 10 L was sufficiently dried, and after nitrogen substitution,6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmolof dicyclo-pentyldimethoxysilane. was added. After replacing thenitrogen in the system with propylene, hydrogen was charged at 0.15MPa-G, and then propylene and ethylene were introduced with stirring.The introduction amount was adjusted so that the ethylene concentrationin the gas phase portion in the polymerization tank was 1.4 mol %.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the pre-polymerization catalyst component (B) with 0.10 mmolin terms of Ti atoms was added. The polymerization was carried out at80° C. for 3 hours while propylene was continuously supplied.

The MFR of the PP component (a) was 45 g/10-min, and the ethylenecontent was 1.8% by mass.

<Manufacturing of Propylene-Based Polymer (A-8)>

The steps (1) and (2) are the same as those of the propylene-basedpolymer (A-1).

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with stirrer and having an internalvolume of 10 L was sufficiently dried, and after nitrogen substitution,6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmolof dicyclo-pentyldimethoxysilane. was added. After replacing thenitrogen in the system with propylene, hydrogen was charged at 0.15MPa-G, and then propylene and ethylene were introduced with stirring.The introduction amount was adjusted so that the ethylene concentrationin the gas phase portion in the polymerization tank was 1.4 mol %.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the pre-polymerization catalyst component (B) with 0.10 mmolin terms of Ti atoms was added, and propylene was continuously added.The polymerization was carried out at 80° C. for 3 hours while beingsupplied to the water.

The MFR of the PP component (a) was 45 g/10-min, and the ethylenecontent was 1.8% by mass.

(3-2) Polymerization-2 (Polymerization [Step 2])

After the polymerization of the PP component (a) was completed (afterthe above [Step 1]), the internal temperature was lowered to 30° C. anddepressurized. Then, hydrogen was charged at 0.94 MPa-G, and then amixed gas of propylene/ethylene: (3.8 L/min)/(1.6 L/min) was introduced.Propylene/ethylene copolymerization was carried out for 50 minutes at aninternal temperature of 60° C. and a total pressure of 0.30 MPa-G(varies depending on the amount of introduced gas).

After a predetermined amount of time had elapsed, 50 mL of methanol wasadded to stop the reaction, and the temperature was lowered anddepressurized. The entire contents were transferred to a filtration tankequipped with a filter, heated to 60° C., and solid-liquid separated.Further, the solid portion was washed twice with 6 L of heptane at 60°C. The propylene/ethylene copolymer thus obtained was vacuum dried.

When the index for the PP component (b) produced in the second stage wascalculated, the production amount was 7% by mass based on the totalweight, the MFR was 7.0 g/10-min, and the ethylene content was 24.5% bymass.

<Manufacturing of Propylene-Based Polymer (A-9)>

The steps (1) and (2) are the same as those of the propylene-basedpolymer (A-1).

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with stirrer and having an internalvolume of 10 L was sufficiently dried, and after nitrogen substitution,6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmolof dicyclo-pentyldimethoxysilane. was added. After replacing thenitrogen in the system with propylene, hydrogen was charged at 0.15MPa-G, and then propylene and ethylene were introduced with stirring.The introduction amount was adjusted so that the ethylene concentrationin the gas phase portion in the polymerization tank was 1.8 mol %.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the pre-polymerization catalyst component (B) with 0.10 mmolin terms of Ti atoms was added. The polymerization was carried out at80° C. for 3 hours while propylene was continuously supplied.

The MFR of the PP component (a) was 45 g/10-min, and the ethylenecontent was 2.3% by mass.

(3-2) Polymerization-2 (Polymerization [Step 2])

After the polymerization of the PP component (a) was completed (afterthe above [Step 1]), the internal temperature was lowered to 30° C. anddepressurized. Then, hydrogen 0.92 MPa-G was charged, and then a mixedgas of propylene/ethylene: (4.0 L/min)/(1.4 L/min) was introduced.Propylene/ethylene copolymerization was carried out for 70 minutes at aninternal temperature of 60° C. and a total pressure of 0.30 MPa-G(varies depending on the amount of introduced gas).

After a predetermined amount of time had elapsed, 50 mL of methanol wasadded to stop the reaction, and the temperature was lowered anddepressurized. The entire contents were transferred to a filtration tankequipped with a filter, heated to 60° C., and solid-liquid separated.Further, the solid portion was washed twice with 6 L of heptane at 60°C. The propylene/ethylene copolymer thus obtained was vacuum dried.

When the index for the PP component (b) produced in the second stage wascalculated, the production amount was 9% by mass based on the totalweight, the MFR was 5.0 g/10-min, and the ethylene content was 20.5% bymass.

<Manufacturing of Propylene-Based Polymer (A-10)>

The steps (1) and (2) are the same as those of the propylene-basedpolymer (A-1).

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with stirrer and having an internalvolume of 10 L was sufficiently dried, and after nitrogen substitution,6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmolof dicyclo-pentyldimethoxysilane. was added. After replacing thenitrogen in the system with propylene, hydrogen was charged at 0.45MPa-G, and then propylene was introduced with stirring.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the pre-polymerization catalyst component (B) with 0.10 mmolin terms of Ti atoms was added. The polymerization was carried out at80° C. for 3 hours while propylene was continuously supplied.

The MFR of the PP component (a) was 180 g/10-min.

(3-2) Polymerization-2 (Polymerization [Step 2])

After the polymerization of the PP component (a) was completed (afterthe above [Step 1]), the internal temperature was lowered to 30° C. anddepressurized. Then, hydrogen was charged at 0.92 MPa-G, and then amixed gas of propylene/ethylene: (3.7 L/min)/(1.7 L/min) was introduced.Propylene/ethylene copolymerization was carried out for 60 minutes at aninternal temperature of 60° C. and a total pressure of 0.30 MPa-G(varies depending on the amount of introduced gas).

After a predetermined amount of time had elapsed, 50 mL of methanol wasadded to stop the reaction, and the temperature was lowered anddepressurized. The entire contents were transferred to a filtration tankequipped with a filter, heated to 60° C., and solid-liquid separated.Further, the solid portion was washed twice with 6 L of heptane at 60°C. The propylene/ethylene copolymer thus obtained was vacuum dried.

When the index for the PP component (b) produced in the second stage wascalculated, the production amount was 8% by mass based on the totalweight, the MFR was 5.0 g/10-min, and the ethylene content was 26.0% bymass.

<Manufacturing of Propylene-Based Polymer (A-11)>

The steps (1) and (2) are the same as those of the propylene-basedpolymer (A-1).

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with stirrer and having an internalvolume of 10 L was sufficiently dried, and after nitrogen substitution,6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmolof dicyclo-pentyldimethoxysilane. was added. After replacing thenitrogen in the system with propylene, hydrogen was charged at 0.15MPa-G, and then propylene and ethylene were introduced with stirring.The introduction amount was adjusted so that the ethylene concentrationin the gas phase portion in the polymerization tank was 1.4 mol %.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the pre-polymerization catalyst component (B) with 0.10 mmolin terms of Ti atoms was added. The polymerization was carried out at80° C. for 3 hours while propylene was continuously supplied.

The MFR of the PP component (a) was 45 g/10-min, and the ethylenecontent was 1.8% by mass.

(3-2) Polymerization-2 (Polymerization [Step 2])

After the polymerization of the PP component (a) was completed (afterthe above [Step 1]), the internal temperature was lowered to 30° C. anddepressurized. Then, hydrogen was charged at 0.92 MPa-G, and then amixed gas of propylene/ethylene: (4.2 L/min)/(1.2 L/min) was introduced.Propylene/ethylene copolymerization was carried out for 100 minutes atan internal temperature of 60° C. and a total pressure of 0.30 MPa-G(varies depending on the amount of introduced gas).

After a predetermined amount of time had elapsed, 50 mL of methanol wasadded to stop the reaction, and the temperature was lowered anddepressurized. The entire contents were transferred to a filtration tankequipped with a filter, heated to 60° C., and solid-liquid separated.Further, the solid portion was washed twice with 6 L of heptane at 60°C. The propylene/ethylene copolymer thus obtained was vacuum dried.

When the index for the PP component (b) produced in the second stage wascalculated, the production amount was 12% by mass based on the totalweight, the MFR was 5.0 g/10-min, and the ethylene content was 19.0% bymass.

<Manufacturing of Propylene-Based Polymer (A-12)>

The steps of (1) and (2) are the same as those of the propylene-basedpolymer (A-1).

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with stirrer and having an internalvolume of 10 L was sufficiently dried, and after nitrogen substitution,6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmolof dicyclo-pentyldimethoxysilane. was added. After replacing thenitrogen in the system with propylene, hydrogen was charged at 0.15MPa-G, and then propylene and ethylene were introduced with stirring.The introduction amount was adjusted so that the ethylene concentrationin the gas phase portion in the polymerization tank was 1.7 mol %.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the pre-polymerization catalyst component (B) with 0.10 mmolin terms of Ti atoms was added. The polymerization was carried out at80° C. for 3 hours while propylene was continuously supplied.

The MFR of the PP component (a) was 45 g/10-min, and the ethylenecontent was 2.2% by mass.

(3-2) Polymerization-2 (Polymerization [Step 2])

After the polymerization of the PP component (a) was completed (afterthe above [Step 1]), the internal temperature was lowered to 30° C. anddepressurized. Then, hydrogen 0.90 MPa-G was charged, and then a mixedgas of propylene/ethylene: (4.4 L/min)/(1.0 L/min) was introduced.Propylene/ethylene copolymerization was carried out for 60 minutes at aninternal temperature of 60° C. and a total pressure of 0.30 MPa-G(varies depending on the amount of introduced gas).

After a predetermined amount of time had elapsed, 50 mL of methanol wasadded to stop the reaction, and the temperature was lowered anddepressurized. The entire contents were transferred to a filtration tankequipped with a filter, heated to 60° C., and solid-liquid separated.Further, the solid portion was washed twice with 6 L of heptane at 60°C. The propylene/ethylene copolymer thus obtained was vacuum dried.

When the index for the PP component (b) produced in the second stage wascalculated, the production amount was 8% by mass based on the totalweight, the MFR was 3.0 g/10-min, and the ethylene content was 16.5% bymass.

<Manufacturing of Propylene-Based Polymer (A-13)>

The steps (1) and (2) are the same as those of the propylene-basedpolymer (A-1).

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with stirrer and having an internalvolume of 10 L was sufficiently dried, and after nitrogen substitution,6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmolof dicyclo-pentyldimethoxysilane. was added. After replacing thenitrogen in the system with propylene, hydrogen was charged at 0.15MPa-G, and then propylene and ethylene were introduced with stirring.The introduction amount was adjusted so that the ethylene concentrationin the gas phase portion in the polymerization tank was 1.4 mol %.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the pre-polymerization catalyst component (B) with 0.10 mmolin terms of Ti atoms was added. The polymerization was carried out at80° C. for 3 hours while propylene was continuously supplied.

The MFR of the PP component (a) was 45 g/10-min, and the ethylenecontent was 1.8% by mass.

(3-2) Polymerization-2 (Polymerization [Step 2])

After the polymerization of the PP component (a) was completed (afterthe above [Step 1]), the internal temperature was lowered to 30° C. anddepressurized. Then, hydrogen was charged at 0.92 MPa-G, and then amixed gas of propylene/ethylene: (4.0 L/min)/(1.4 L/min) was introduced.Propylene/ethylene copolymerization was carried out for 50 minutes at aninternal temperature of 60° C. and a total pressure of 0.30 MPa-G(varies depending on the amount of introduced gas).

After a predetermined amount of time had elapsed, 50 mL of methanol wasadded to stop the reaction, and the temperature was lowered anddepressurized. The entire contents were transferred to a filtration tankequipped with a filter, heated to 60° C., and solid-liquid separated.Further, the solid portion was washed twice with 6 L of heptane at 60°C. The propylene/ethylene copolymer thus obtained was vacuum dried.

When the index for the PP component (b) produced in the second stage wascalculated, the production amount was 7% by mass based on the totalweight, the MFR was 5.0 g/10-min, and the ethylene content was 21.0% bymass.

<Manufacturing of Propylene-based Polymer (A-14)>

The steps (1) and (2) are the same as those of the propylene-basedpolymer (A-1).

(3-1) Polymerization-1 (Polymerization [Step 1])

A stainless-steel autoclave equipped with stirrer and having an internalvolume of 10 L was sufficiently dried, and after nitrogen substitution,6 L of dehydrated heptane, 12.5 mmol of triethylaluminum, and 0.6 mmolof dicyclo-pentyldimethoxysilane. was added. After replacing thenitrogen in the system with propylene, hydrogen was charged at 0.15MPa-G, and then propylene and ethylene were introduced with stirring.The introduction amount was adjusted so that the ethylene concentrationin the gas phase portion in the polymerization tank was 1.4 mol %.

After the inside of the system was stabilized at an internal temperatureof 80° C. and a total pressure of 0.8 MPa-G, 20.8 mL of a heptane slurrycontaining the pre-polymerization catalyst component (B) with 0.10 mmolin terms of Ti atoms was added. The polymerization was carried out at80° C. for 3 hours while propylene was continuously supplied.

The MFR of the PP component (a) was 45 g/10-min, and the ethylenecontent was 1.8% by mass.

(3-2) Polymerization-2 (Polymerization [Step 2])

After the polymerization of the PP component (a) was completed (afterthe above [Step 1]), the internal temperature was lowered to 30° C. anddepressurized. Then, hydrogen was charged at 0.96 MPa-G, and then amixed gas of propylene/ethylene: (4.9 L/min)/(0.5 L/min) was introduced.Propylene/ethylene copolymerization was carried out for 50 minutes at aninternal temperature of 60° C. and a total pressure of 0.30 MPa-G(varies depending on the amount of introduced gas).

After a predetermined amount of time had elapsed, 50 mL of methanol wasadded to stop the reaction, and the temperature was lowered anddepressurized. The entire contents were transferred to a filtration tankequipped with a filter, heated to 60° C., and solid-liquid separated.Further, the solid portion was washed twice with 6 L of heptane at 60°C. The propylene/ethylene copolymer thus obtained was vacuum dried.

When the index for the PP component (b) produced in the second stage wascalculated, the production amount was 7% by mass based on the totalweight, the MFR was 8.0 g/10-min, and the ethylene content was 9.0% bymass.

<Elastomer (B)>

As the elastomer (B), the following ethylene-α-olefin copolymers (B-1)to (B-3) were used.

(B-1) Metallocene-Based Ethylene-α-Olefin Copolymer:

-   -   Density (measured according to JIS K7112. Hereinafter, it may be        abbreviated as density.): 903 kg/m³,    -   MFR (190° C.): 15 g/10-min    -   (manufactured by Prime Polymer Co. Ltd., trade name: SP00206)

(B-2) Metallocene-Based Ethylene-α-Olefin Copolymer:

-   -   Density: 883 kg/m³,    -   MFR (190° C.): 20 g/10-min    -   (manufactured by Mitsui Chemicals, Inc, trade name: A-2085S)

(B-3) Metallocene-Based Ethylene-α-Olefin Copolymer:

-   -   Density: 913 kg/m³,    -   MFR (190° C.): 4.0 g/10-min    -   (manufactured by Prime Polymer Co. Ltd., trade name: SP1540)

[Granulation/Molding/Evaluation] <Granulation/Molding>

(1) Granulation:

In the formulation shown in the Table (Examples/Comparative Examples),the propylene-based polymer (A), the elastomer (B),dimethyl-2-(4-hydroxy-2,2,6,6-tetramethyl-1-piperidyl) ethanolcondensate (“TINUVIN 622” (trade name), manufactured by BASF) as theweather-resistant stabilizer, and nonitol1,2,3-trideoxy-4,6:5,7-bis-O-[(4-propylphenyl) methylene] (“MirroredNX8000J” (trade name), manufactured by Milliken) or (C-1):2,2′-methylenebis(4,6-di-tert-butylphenyl) aluminum phosphate (“ADK STABNA-21” (trade name), manufactured by ADEKA CORPORATION) as a nucleatingagent were formulated in a predetermined amount, and then additives of0.13 parts by mass of phosphorus-based antioxidant:tris(2,4-di-t-butylphenyl) phosphite (“Irgafos 168” (trade name)manufactured by BASF) and 0.10 parts by mass of a neutralizing agent:calcium stearate (NITTO KASEI CO., LTD.) were further stirred and mixedby a Henshell mixer.

The obtained mixture was melt-kneaded under the following conditionsusing a twin-screw extruder (TEM35BS) manufactured by TOSHIBA MACHINECO., LTD. to obtain strands.

Model: TEM35BS (35 mm twin-screw extruder)

Screw rotation speed: 300 rpm

Screen mesh: #200

Resin temperature: 230° C.

The obtained strands were cut by a pelletizer after water cooling toobtain pellets of the propylene resin composition.

(2) 10 mL-Syringe Molding

A container was molded by the following method using the pellets of thepropylene resin composition.

Pellets of the propylene-based resin composition were injection-moldedinto a 10 mL-syringe having a height of 80 mm, a diameter of 16 mm, anda side wall thickness of 1.0 mm, using an electric injection moldingmachine with a mold clamping force of 140 tons (NEX140IV manufactured byNISSEI PLASTIC INDUSTRIAL CO., LTD.), under the conditions of cylindertemperature: 230° C., mold temperature: 25° C., injection primarypressure: 130 MPa, injection speed: 50 mm/sec, holding pressure: 150MPa, and holding time: 5.0 sec.

(3) High-Speed Moldability

In continuous molding under the above molding conditions, the minimumcycle time. that enables molding with free from troubles such as moldrelease failure between 100 shots, syringe deformation, and containerflow direction damage due to the orientation of the elastomer resin, wasmeasured.

<Physical Property Evaluation>

(4) MFR

The melt flow rates MFR of the propylene-ethylene copolymers (a) and (b)of the present invention and the propylene-ethylene resin composition(A) were measured according to JISK-7210-1999 (230° C., 2.16 kg-load),and the MFR of elastomer (B) was measured according to JISK-7210-1999(190° C., 2.16 kg-load).

(5) Ethylene Content (¹³C-NMR Measurement Conditions)

-   -   Measuring device: LA400-type nuclear magnetic resonance device        manufactured by JEOL Ltd.    -   Measurement mode: BCM (Bilevel Complete decoupling)    -   Observation frequency: 100.4 MHz    -   Observation range: 17006.8 Hz    -   Pulse width: C nucleus 45° (7.8 μs)    -   Pulse repetition time: 5 seconds    -   Sample tube: 5 mmφ sample tube    -   Rotation speed: 12 Hz    -   Integration frequency: 20000 times    -   Measurement temperature: 125° C.    -   Solvent: 1,2,4-trichlorobenzene: 0.35 ml/Benzene-d6: 0.2 ml    -   Sample amount: Approximately 40 mg

From the spectrum obtained by the measurement, the ratio of the monomerchain distribution (triad (triplet) distribution) was determinedaccording to the following document (1), and the mole fraction (mol %)of the constituent unit derived from ethylene was determined(hereinafter referred to as E (mol %)) and the mole fraction (mol %) ofthe constituent unit derived from propylene (hereinafter referred to asP (mol %)) were calculated. The content (% by mass) of the constituentunit derived from ethylene of the propylene-ethylene copolymer(hereinafter E (wt %)) was calculated by converting the obtained E (mol%) and P (mol %) into mass % according to the following (Equation 1).

E(wt %)=E(mol %)×28×100/[P(mol %)×42+E(mol %)×28]  (Equation 1)

Document (1): Kakugo, M.; Naito, Y.; Mizunuma, K.; Miyatake, T.,Carbon-13 NMR determination of monomer sequence distribution inethylene-propylene copolymers prepared with delta-titaniumtrichloride-diethylaluminum chloride. Macromolecules 1982, 15, (4),1150-1152

(6) Tensile Modulus:

A test piece was molded by an injection molding method, and aftermolding, it was left in a constant temperature room adjusted to a roomtemperature of 23±5° C. and a relative humidity of 50±5% for 72 hours,and then the tensile modulus was obtained in compliance with JIS K 7161(ISO178).

The tensile modulus after radiation sterilization was obtained bymeasuring as follows: After molding a 10-mL syringe, it was left in aconstant temperature room adjusted to a room temperature of 23±5° C. anda relative humidity of 50±5% for 72 hours, γ-ray of 25 kGy (averagedose) was irradiated under room temperature conditions and under an airatmosphere. After irradiating, the condition was further adjusted in aconstant temperature room at room temperature of 23° C.±0.5° C. andrelative humidity of 50±5% for 2 weeks, and then the measurement wasperformed.

(7) Impact Resistance of 10-mL Syringe (Weight-Drop Test)

The state of the 10-mL syringe was adjusted under the condition of 23°C. for 48 to 72 hours, and further the state was adjusted for 24 hoursor more in an environment of 10° C.

In the environment of 10° C., an iron rod (13.5 mmϕ, 120 g) was droppedvertically with respect to the center of the body of the syringe, andthe maximum height at which cracks did not occur when dropped 10 timeswas measured.

In the weight-drop test after radiation sterilization, after molding a10-mL syringe, the product was left in a constant temperature roomadjusted to a room temperature 23±5° C. and a relative humidity of 50±5%for 72 hours, and then γ-ray of 25 kGy (average dose) was irradiatedunder room temperature conditions and under an air atmosphere. Afterirradiating, the state of syringe was further adjusted in a constanttemperature room at room temperature of 23° C.±0.5° C. and relativehumidity of 50±5% for 2 weeks, and then the measurement was performed.

(8) Transparency of 10 mL Syringe (Light Transmittance in Water)

With reference to 17th revised Japanese Pharmacopoeia Test 7.02Plastic-made Drug Container Test Method 1.4 Transparency Test, the testwas carried out by the following method:

From the height of the body of the container around 40 mm, cut 5 piecesinto a size of about 0.9×4 cm, and immersed each in a water-filled UVabsorption spectrum measurement cell, the transmittance of the cut pieceat a wavelength of 450 nm was measured using a cell filled only withwater as a control and determined by an ultraviolet visibleabsorptiometry.

The light transmittance in water after radiation sterilization wasmeasured after molding a 10-mL syringe, the product was left in aconstant temperature room adjusted to a room temperature 23±5° C. and arelative humidity of 50±5% for 72 hours, and then γ-ray of 25 kGy(average dose) was irradiated under room temperature conditions andunder an air atmosphere. After irradiating, the state of syringe wasfurther adjusted in a constant temperature room at room temperature 23°C.±0.5° C. and relative humidity 50±5% for 2 weeks, and then themeasurement was performed.

(9) JIS T3210: 2011—Sterile Injection Syringes 6. Chemical Requirements—

With reference to this standard, the chemical requirements were testedby the following method.

(a) Preparation of 100 mm×120 mm×1 Mmt Press Sheet

A spacer for obtaining a 100 mm×120 mm×1 mmt press sheet was placedbetween 150 mm×150 mm×3 mmt aluminum plates, and a specified amount ofpellets was placed in the frame of the spacer. Then, using a heatingpress heated to 230° C., the pellets were melted in the heating pressmachine without applying pressure for the first 7 minutes, and then apressure of 100 kg/cm² was applied for 3 minutes. Thereafter, the samplewas immediately transferred to a cooling press at 30° C. and a pressureof 150 kg/cm² was applied for 2 minutes to cool the sample. Then, thepress sheet was released from the aluminum plate and the spacer andtaken out.

(b) Preparation of Test Piece for Elution Test

The press sheet prepared in (a) was evenly divided into four withscissors, and four sheets of 60 mm×50 mm×2 mmt were collected. Then, thesheet surface and the cut surface were washed with distilled water anddried at room temperature to obtain a test piece for an eluate test.

(c) Radiation Sterility of the Test Piece

After irradiating the test piece with γ-rays of 25 kGy (average dose)under air atmosphere and room temperature conditions, the state of thetest piece was adjusted in a constant temperature room with a roomtemperature of 23° C.±0.5° C. and a relative humidity of 50±5% for 2weeks.

(d) Preparation of Test Solution

250 ml of distilled water was placed in a 500-ml glass beaker made ofborosilicate, which was washed with distilled water and dried at roomtemperature. Four test pieces (60 mm×50 mm×2 mmt) for the eluate testprepared in (C) were put therein and immersed in water. At that time, nobubbles remained on the surface of the test piece. Then, the beaker wassealed with aluminum foil and kept at 37° C. for 8 hours in a constanttemperature bath, and then the test piece was taken out and used as atest solution.

(E) pH Test, Elution Metal Test

The test was carried out according to the method described in JIS T3210:2011. Distilled water was used as the blank test solution, and theeluted metal was analyzed by the atomic absorption spectrophotometricmethod.

The criteria for each test result are as follows. The suitability wasevaluated.

(i) ΔpH: The difference in pH between the test solution and the blanktest solution is 1 or less.(ii) The total amount of the eluted metals: lead, zinc and iron is 5mg/L or less and the cadmium content of the test solution is 0.1 mg/L orless when the cadmium measured value of in the test solution iscorrected with the cadmium measured value of the blank test solution.

(10) Yakuhatsu No. 494 Dialysis Artificial Kidney Device ApprovalCriteria, IV Blood Circuit Quality and Test Method

Currently, “Yakuhatsu No. 494 Dialysis Artificial Kidney Device ApprovalCriteria” is “Abolition of notification”. However, since this test is aguideline for confirming the chemical safety in this application, thetest was conducted.

Heavy metal tests, lead tests, and cadmium tests (collectively referredto as ashing tests) were conducted using pellets in accordance with theoperating method of the approval criteria. The pellets used in the testwere sterilized by irradiation with γ-rays of 25 kGy (average dose) 2weeks before the main test, and the state was adjusted in a constanttemperature room at room temperature of 23° C.±0.5° C. and relativehumidity of 50±5% for 2 weeks.

In addition, the eluate test was carried out with reference to theeluate test described on ‘V the quality and test method of the dialyzer,5. the support and blood connection tube within this approval standard,by adding 150 ml of water to 15 g of pellets, and then performing anextraction test at 70° C. for 1 hour in compliance with the operationmethods of the approval standard for each test. The pellets used in thetest were sterilized by irradiation with γ-rays of 25 kGy (average dose)at 2 weeks before this test, and the state of the pellets was adjustedin a constant temperature room at room temperature of 23° C.±0.5° C. andrelative humidity of 50±5% for 2 weeks.

The criteria for each test result are as follows. The suitability wasevaluated.

4. Heavy metal test: 10 μg/g or less5. Lead test: 1 μg/g or less6. Cadmium test: 1 μg/g or less8. Eluent test

-   -   (i) Appearance: colorless and transparent, no foreign matter    -   (ii) Foaming property: disappears within 3 minutes    -   (iii) ΔpH: difference from blank is 1.5 or less    -   (iv) Zinc: standard solution (0.5 μg/g) or less    -   (v) Potassium permanganate (KMnO₄) reducing substance:        Difference in consumption of potassium permanganate from        standard solution is 1.0 ml or less.    -   (vi) Evaporation residue: 1.0 mg or less    -   (vii) Ultraviolet absorption spectrum (UV) at 220-350 nm: 0.1 or        less    -   *) Currently, “Yakuhatsu No. 494 Dialysis Artificial Kidney        Device Approval Criteria” is “Abolition of notification”.        However, since this test is a guideline for confirming the        chemical safety in this application, the test was conducted.

TABLE 1 Examples Comparative Examples Unit 1 2 3 4 5 6 1 Propylene-Preparation — A-1 A-2 A-3 A-4 A-5 A-6 A-7 based Example polymer (A)Blending part by mass 93 93 93 90 95 90 90 amount Propylene- Weight % bymass 93 93 93 93 93 95 100 ethylene Ethylene % by mass 1.8 1.8 1.8 2.33.0 2.3 1.8 copolymer (a) content MFR g/10-min 45 45 45 45 45 45 45(230° C.) Propylene- Weight % by mass 7 7 7 7 7 5 — ethylene Ethylene %by mass 18.0 19.0 21.0 21.0 21.0 21.0 — copolymer (b) content MFRg/10-min 7.0 3.0 5.0 5.0 5.0 5.0 — (230° C.) Elastomer Ethylene-Preparation — B-1 B-1 B-1 B-1 B-2 B-1 B-1 (B) α-olefin Example copolymerBlending part by mass 7 7 7 10 5 10 10 amount MFR g/10-min 15 15 15 1520 15 15 (190° C) Density kg/m³ 903 903 903 903 883 903 903 Weatherresistant stabilizer part by mass 0.04 0.04 0.04 0.04 0.04 0.04 0.04Nucleating agent Type — NX8000J NX8000J Content part by mass 0.4 0.4 0.40.4 0.4 0.4 0.4 Comparative Examples Unit 2 3 4 5 6 7 8 Propylene-Preparation — A-8 A-9 A-10 A-11 A-12 A-13 A-14 based Example polymer (A)Blending part by mass 93 100 80 97 97 93 93 amount Propylene- Weight %by mass 93 91 92 88 92 93 93 ethylene Ethylene % by mass 1.8 2.3 0 1.82.2 1.8 1.8 copolymer (a) content MFR g/10-min 45 45 180 45 45 45 45(230° C.) Propylene- Weight % by mass 7 9 8 12 8 7 7 ethylene Ethylene %by mass 24.5 20.5 26.0 19.0 16.5 21.0 9.0 copolymer (b) content MFRg/10-min 7.0 5.0 5.0 5.0 3.0 5.0 8.0 (230° C.) Elastomer Ethylene-Preparation — B-1 — B-3 B-1 B-2 B-1 B-1 (B) α-olefin Example copolymerBlending part by mass 7 — 20 3 3 7 7 amount MFR g/10-min 15 — 4 15 20 1515 (190° C) Density kg/m³ 903 — 913 903 883 903 903 Weather resistantstabilizer part by mass 0.04 0.04 — 0.04 0.04 — 0.04 Nucleating agentType — NX8000J NA-21 NX8000J Content part by mass 0.4 0.3 0.2 0.4 0.30.4 0.4

TABLE 2 Examples Comparative Examples Unit 1 2 3 4 5 6 1 2 3 4 5 6 7 8<Physical properties> Before MFR g/10- 26 30 27 28 28 30 42 34 27 60 2225 29 32 sterility min with 25 Tensil Modulus MPa 1180 1250 1250 12301100 1250 1490 1380 1270 1250 1060 1210 1250 1300 kGy γ-ray Weight Drop10-mL cm 150 150 100 150 150 150 20 40 5 150 100 10 150 10 Test (10° C.)Syringe Light 10-mL % 70 70 70 70 71 70 67 66 50 45 67 62 70 70transmittance Syringe in water After Tensil Modulus MPa 1200 1270 12701250 1120 1270 1510 1400 1290 1270 1080 1230 1270 1320 sterility WeightDrop 10-mL cm 20 10 10 10 10 10 ≤5 10 ≤5 ≤5 10 ≤5 ≤5 ≤5 with 25 Test(10° C.) Syringe kGy γ-ray Light 10-mL % 70 70 70 70 71 70 67 66 50 4567 62 70 70 transmittance Syringe in water Elusion after Elute Test*¹Propriety — Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yes Yessterility Ashing Test*² Propriety — Yes Yes Yes Yes Yes Yes Yes Yes YesYes Yes Yes Yes Yes with 25 Elute Test*² Propriety — Yes Yes Yes Yes YesYes Yes Yes Yes Yes Yes Yes Yes Yes kGy γ-ray <Molding evaluation of10-mL syringe> High speed moldability Cycle time sec. 15 15 15 17 17 1715 15 15 23 21 15 15 15 *¹JIS T3210: 2011 -Sterile injection syringes 6.Chemical Requirements- *²Yakuhatsu No. 494 Dialysis Artificial KidneyDevice Approval Criteria, IV Blood Circuit Quality and Test Method

1. An injection-molded article for medical use obtained by using a medical propylene-ethylene-based resin composition, wherein the medical propylene-ethylene-based resin composition comprises: 88 to 95 parts by mass of a propylene-ethylene resin composition (A) that contains more than 90% by mass and equal to less than 97% by mass of a propylene-ethylene copolymer (a) having an ethylene content of 1 to 5% by mass, and a melt flow rate (hereinafter, abbreviated as MFR) conforming to JIS K7210 (230° C., 2.16 kg load) being 10 to 100 g/10-min, and equal to more than 3% by mass and less than 10% by mass of a propylene-ethylene copolymer (b) having an ethylene content of 15 to 22% by mass and an MFR of 1 to 50 g/10-min, (with the proviso that the total of (a) and (b) is 100% by mass), 5 to 12 parts by mass of an elastomer (B) that is an ethylene-α-olefin random copolymer which is an ethylene-α-olefin random copolymer having a density of 0.880 to 0.920 g/cm³ (with the proviso that the total of (A) and (B) being 100 parts by mass); and 0.01 to 0.20 parts by mass of a weather-resistant stabilizer, and wherein the injection-molded article has been sterilized by γ-ray or electron beam.
 2. The injection-molded article for medical use according to claim 1, wherein the elastomer (B) is an ethylene-α-olefin random copolymer polymerized using a metallocene catalyst and having an MFR of 1 to 100 g/10 min in accordance with JIS K7210 (190° C., 2.16 kg load).
 3. The injection-molded article for medical use according to claim 1, wherein the medical propylene-ethylene-based resin composition further comprises a nucleating agent. 